XenApp 7.6 Upgrade – You got questions, I got answers

Recently, I gave a webinar (recorded for your viewing pleasure) on upgrading to XenApp 7.6, and while this webinar is just one of many efforts Citrix is doing to help everyone make the upgrade to XenApp 7.6, there was a big turnout. Citrix has a website (www.citrix.com/xenapp/upgrade) dedicated to helping all of you, who are looking at upgrading your existing XenApp to 7.6, with links to resources, free training, special support programs, and more.

I’d like to thank all of you for attending and for submitting some really great questions, which I’ll try to answer.

Q: Does connection leasing allow users without a current session to connect to Citrix apps while the database is down?

A: Yes. The delivery controller will keep a list of previous connections from the user. Those previously used connection parameters will be used in the future if the database is unavailable. The default timeframe is 2 weeks, but this can be modified with PowerShell. Leo Singleton wrote a great blog on the ins and outs of connection leasing.

Q: Is the local text echo functionality part of XenApp 7.6?

A: HDX has been enhanced over many years to improve upon the responsiveness and interactivity of the user session, something Local Text Echo did but in a slightly different manner. So Local Text Echo, as it was in 6.5, is not part of 7.6, but HDX includes interactivity enhancements that make the need for Local Text Echo obsolete.

Q: How much RAM should one give to the “Cache in RAM with overflow to disk” feature for XenApp 7.6?

A: Any amount will be a benefit. I’ve seen 1, 2 and 3GB of RAM allocated per VM show significant value to a XenApp VM resulting in IOPS of less than 1 per user. Read more on Overflow to disk for XenApp on my blog on ‘Changing the read/Write Ratio for XenApp’

Q: When migrating (not rebuilding), does the XenApp server have IMA and FMA running at the same time?

A: No. When you are ready to migrate a XenApp 6.5 worker to the XenApp 7.6 site, the upgrade wizard will remove the 6.5 worker from the farm, uninstall the 6.5 software and install the 7.6 VDA while placing the server into the 7.6 site.

Q: Is there a difference/risk in using the migration tool over doing a rebuild of the farm (assuming that the underlying operating system isn’t changing)?

A: Migrating the farm and policy settings via the migration tool is just a time saver, especially for large, complex environment. As for the XenApp workers, many people prefer to rebuild in that it is an opportunity to refresh the server back to a clean state (assuming you aren’t using something like PVS for image management). The benefit of the upgrade wizard for the workers is that you don’t have to go through the app install/configuration again.

Q: What steps must I do to upgrade from Version 7.5 to 7.6 and in which steps?? License Server? Delivery Controller? Storefront? Director? VDA’s? What is the right order?

Q: If my policies are stored in Active Directory instead of XenApp, do I need to run the Policy Export utility?

A: No, the export/import is only for Farm stored information. For AD policies, you will continue to use them

Q: Does the import farm utility also include application icons?

A: Yes. The icons are exported and imported as part of the migration utility

Q: Does the migration utility work for XenApp 6?

A: Yes, although it is experimental. The commands used to gather the farm, policy and application settings from XenApp 6.5 are the same in XenApp 6.0, but the migration utility has not been tested nearly as in-depth as XenApp 6.5.

Q: In XenApp 6.5, if we launch two different apps that are both hosted from the same server, it only creates 1 session. Is this still the case in 7.6?

Q: Is App-V required for XenApp 7.6 if I would still like to stream my applications like I did in XenApp 6.5?

A: Yes. Application Streaming that was part of XenApp 6.5 has been replaced with Microsoft App-V. XenApp 7.6 includes integration with App-V to simplify publishing and integration.

Q: I’m already on XenApp 7.5. Is it worthwhile to go to XenApp 7.6?

A: You will want to review the following page (http://www.citrix.com/products/xenapp/whats-new.html) as well as the webinar on What’s New in XenApp 7.6. Once you are on XenApp 7.x, the upgrade process is easy in that you can do in place upgrades on a component-by-component basis. So you can have 1 controller on 7.6 and another on 7.5 while your VDAs are on 7.5. This allows you to take your time for doing the upgrade instead of doing a big band type deployment.

Q: We are on XenApp 4.5 and are deciding on upgrading to 6.5 or 7.6. Which version would you recommend?

A: As XenApp 4.5 is a Window 2003 solution, you are correct that the time to upgrade is now. I would recommend you move to the latest Windows operating system (2012R2), which will give you the longevity over anything else. Plus, if you start with XenApp 7.6, you won’t have to think about the upgrade from 6.5 to 7.6.

Q: If we have a multiple geographical location deployment of XenApp 6.5 utilizing zones, does this mean we will need to implement delivery controllers, SQL servers, etc at each location?

A: Assuming those geographical locations are not connected with a low latency connection, then yes, you will have a XenApp site at each location. Depending on the size of those sites, this might be beneficial as this will allow you to build smaller failure domains, as each site is independent, a fatal error at one site will not bring down another site. However, for XenApp 6.5 deployments with many small zones of only a few servers each, if you are unable to consolidate into a single data center, you will want to remain on XenApp 6.5 for the time being.

Q: Can a XenApp 7.6 site include Windows 2008 and 2012 servers?

A: Yes. Based on the new FMA architecture you can have a single site using Windows 2008R2, Windows 2012 and 2012R2.

Q: What happens if one of the delivery controllers goes offline? Is there a service failure?

A: No. In XenApp 7.6, all delivery controllers within a site are Active-Active. If you recall, in XenApp 6.5 and previous versions, you have a Zone Data Collector, and if that data collector fails, a new one will be elected, which also might be hosting apps. This has caused performance issues if not configured correctly. This risk is no longer relevant in XenApp 7.6

Q: How do we configure the app aggregation feature of StoreFront and the user grouping in Web Interface?

Q: If I upgrade to XenApp 7.6 from 7.5, do I have to upgrade StoreFront? Do I have to upgrade Web Interface to Storefront?

A: No. You can stay on your current version. However, there might be a situation where a new feature in XenApp will not work with an older component or you won’t be able to use a new StoreFront feature.

Q: What file do you use to configure the StoreFront App Aggregration feature?

A: Located here: C:\inetpub\wwwroot\Citrix\storename\web.config, where “storename” is the name of your store. Also, make a backup copy of your web.config file before modifying.

Q: With regards to the database, what information is there on High Availability?

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Daniel Feller is a Lead Architect at Citrix. With a app and desktop virtualization history dating back to 1997, Daniel has participated in many different deployments taking on many different roles. After graduating from Purdue University, Daniel started out as an IT Admin deploying WinFrame and MetaFrame 1.0. Daniel soon joined Citrix Consulting as one of the first consultants and spent many years working on some of the world's largest and most complex environments. In addition to field projects, Daniel has also authored several well known whitepapers like the XenDesktop Design Handbook and created the intricate logic behind Citrix Project Accelerator. Daniel can usually be seen speaking at conferences focusing on design topics for application and desktop virtualization.